1. Technical Field
The present invention relates to devices and methods for measuring adhesion strength between two optical elements.
2. Description of Related Art
Generally, image pick-up devices such as charge coupled devices (CCD) or complementary metal oxide semiconductors (CMOS) used in, for example, cameras, react to light even in the near-infrared region beginning at a wavelength of about 700 nanometers and in the infrared (IR) region. However, light in the near-infrared and IR regions causes crosstalk that reduces a signal-to-noise ratio of the image pick-up device and thereby deteriorating the device's reproduction ability. In order to prevent such reaction and crosstalk, IR cut filters that block light in the near-infrared and IR regions are assembled in lens modules implemented in conventional cameras.
In a conventional lens module, the IR-cut filter is usually attached to a spacer using glue. However, the usage of glue has adhesion and reliability problems. The IR-cut filter may become separated from the lens module due to weak adhesion strength. Therefore, it is necessary to measure the adhesion strength between the IR-cut filter and the spacer in lens module manufacturing.
It is therefore desirable to find a device and a method which can overcome the above mentioned problems.